Generally in surgical procedures, a practitioner makes an incision in the body of a patient in order to repair damaged tissue, modify tissue, remove tissue or to insert some sort of implantable device. Many procedures are combinations of these procedures. One example of such a combination is found in cataract surgery. Cataract surgery is performed to remove the lens of a patient's eye that has become substantially or partially opaque having an adverse effect on the patient's visual acuity. Practitioners have found that if the opacified lens is removed and replaced with an implantable intraocular lens (IOL), there are significant improvements in the patient's visual acuity. In order to perform this procedure, the practitioner makes an incision in the patient's eye sufficient to remove the non-functional lens and insert an appropriate IOL. The incision to facilitate the removal and replacement of the lens is made in the cornea or sclera of the eye. The incision provides the practitioner with access to the lens so that it may be removed.
There are a number of different procedures that are used to remove a non-functional lens from the eye, the most commonly practiced are referred to as extracapsular surgery and phacoemulsification. In extracapsular surgery, the practitioner removes the lens while allowing the posterior lens capsule to remain. In phacoemulsification, the practitioner reduces the lens to an emulsion by careful application of ultrasonic energy coupled with irrigation and suction, thereby removing the non-functional lens. In both of these procedures, the removed lens is then replaced by a synthetic polymeric IOL substantially restoring the visual acuity of the eye.
A critical component of this procedure is the incision that provides the practitioner with access to the non-functional natural lens so that it can be removed. The ideal incision for a lens removal and replacement is of a minimum size and accurately placed. The incision through which the several instruments used to conduct the procedure is preferably an opening substantially the same circumference as the instruments. Accurate sizing minimizes trauma to the eye and facilitates healing of the eye after the procedure is completed. In the case of the phacoemulsion procedure, if the incision is too small, corneal tissue adjacent the incision may be damaged by contact with the ultrasonic probe and alternatively, if the incision is too large, leakage from the eye may cause prolapse and loss of endothelial cells.
Another problem related to the incision in cataract surgery is suture induced astigmatism. An incision made in the eye must be closed after the procedure so that healing occurs and that there is no path for infection. Previously, sutures have been used to close the incision. A suture may alter the shape of the eye and result in astigmatism. Additionally, sutures may cause irritation, provide a location for infection and abscess or a foreign body reaction. Recently, sutureless techniques have been devised that allow the practitioner to make an incision of a particular shape or geometry that utilize the internal pressure in the eye to keep the incision closed until it heals without the use of sutures. Making such an accurately placed and sized incision for such a procedure is very technique sensitive. Apparatus and methods for making a properly sized and shaped incision for cataract removal procedures are available, but are still subject to variations in technique. If a device that made a practitioner's placement and sizing of an incision in the eye less technique sensitive, the art of eye surgery would be advanced. Such a device and a method for its use is disclosed hereinbelow.